Preliminarily, I wish to refer generally to the following U.S. Pat. Nos. 2,791,994; 3,284,762; 2,907,648; 3,155,141; 2,791,990; 1,939,302; 3,533,606; 3,016,233; 2,704,535; and British Pat. No. 723,797, as possibly being of interest. U.S. Pat. No. 2,907,648 relates to electrostrictive and magnetostrictive devices which apparently produce ultrasonic energy. The method of this invention is extremely efficient, practical and inexpensive. The system of this invention comprises a cylindrical piezoelectric ceramic transducer vibrating in the "hoop" mode or radial mode and being electrically driven by an oscillator and power amplifier. The transducer is in an "unloaded" condition (High Q); therefore, when the fuel strikes the surface it is immediately atomized or vaporized. It is to be expected that this invention will find rapid application in internal combustion engines to bring said engines into conformity with the increasing stringent standards for the control of exhaust pollution caused by such engines. This invention eliminates the need for expensive and undependable exhaust after-treatment devices by effectively dealing with the problem at the intake side of the engine.